Strain insulator



Patented June 28, 1932 UNITI-:D STATES vPMENT OFFICE BURTON ".M. SMALLEY, OF CHICAGO, ILLINOIS, ASSIGNOR TO .'.I'OSLYN MANUFACTUR- ING AND SUPPLY CO., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS sfrmlIN INsULA'roB Application md August 2s, 192s. serial No. 301,464.

stock in order, to accommodate all sizes of insulators, but none of them would accurately it any of the insulators, since they were of rigid material and the insulators cannot' be made perfectly true, so that a one or two point engagement with the insulators resulted which caused excessive strain on these points.

When excessive strains are present, the ini sulator may be broken, or if not broken the enamel may be chipped, lexposing the porous inner portion of the insulator to the atmosphere and weather.- Such a strainon a particular point of a clevis of rigid construction may cause the same to break and elongate and thereby transfer all or nearly all of lthe strain to the thinner side portion of the insulator which may crush the same.

The object of my invention is, therefore to provide a clevis for a strain insulator which will overcome these diiiicultics and I have provided a mechanism which is relatively flexible fo'r uniformly distributing strain around and over the contact area. My clevis is adapted to it insulators of a number ofsizes so that the stock sizes of the clevis may be greatly reduced in number. Other objects and advantages will hereinafter appear.

My invention is arranged to be used with a standard form of strain insulator having an arcuate bore through the body part, one

side of which is a contact area for engage! ment by the clevis and having grooves extending longitudinally from the end of the bore. Through the arcuate bore I pass a relatively flexible element which uniformly engages the contact area. The flexible element is provided with means for securing the same to a crossbar or the like which, in turn, is engaged by a cable or rod transmitting the strain. y

In the accompanying drawing andfor the purpose 'of illustration I have shown a specific illustration of theI preferred form of my invention..

Fig. 1 is an elevational view of a strain insulator, incorporating my invention;

Fig. 2 is a longitudinal section taken on substantially the line 2 2 of Fig. 1;

Fig. 3 is a right end elevation of that shown in Fig. 2;

Fig. 4 is a plan view, showing the manner in which the flexible element is cut for welding to the stud bolt; and,

Fig. 5 is a plan view similar to Fig. 4, but showing the elements welded and the bolt threaded, as in the completed device.

`The porcelain insulator 10 is preferably of any well known make and construction and'is provided with a bore 11, one side 12 of which is arcuate in shape and adapted to receive strains from the flexible cable 13, which lits snugly and uniformly on the arcuate area from the point 14 and 15', as shown in Fig.

2. The grooves 16, extending longitudinally of the insulator are adapted to receive the forwardly extending portionsy of the iexible I'cable 13, for holding the insulator in correct position.

4The bore 17 and the grooves 18 are similar to the bore `11 and grooves 16, but are arranged at right angles thereto and adapted to receive strain in the opposite direction. The cable 13 is preferably of stranded form. In order that the cross-bar 19 spanning the distance between the ends of the cable may beoperatively secured thereto, I cut the cablev 13 on an angle, as shown at 20 in Fig. 4. The

cable 13 and bolts 22 are aligned and brought v high resistance to the flow of electric current,

produces a welding heat which melts the metal and facilitates the welding operation. The weld, as completed, is shown at 23 in Fig. 5 and the studbolt 22 is threaded at 24. The cross-bar 19 is preferably of cast or 5 forged material and is of sufficient size to withstand all strains to which it may be subjected in normal use. The bar is bent at 25, in order that the strain-transmitting member 26 may be retained in the center of the bar, 10 as shown in Fig. 2. The ends 27 of the crossbar are flattened for engagement with the bottoms of the nuts 28 and flanges 29 engage the sides of the nuts to lock them in position after they have been adjusted the desired amount.

While I have described the cross-bar or yoke 19 as being cast or forged, I also contemplate pressing this member out of sheet metal of suitable gauge and temper.

It will be apparent to those skilled in the art that I have provided a strain insulator clevis which has much greater mechanical strength than those heretofore in use, that it has much less destructive effect upon the insulator, and is adaptable to many sizes of insulators, and that I have incorporated therein a novel means for locking the securing nuts in place on their respective bolts. It will also be apparent that this may be modified 80 without departing from the spirit of the invention, and I do not intend to be limite-d by the details herein illustrated and described,

but desire to avail myself of such variations and modifications as come within the scope 8.. of the appended claim.

I claim:

A clevis for a straininsulator including a substantially U-shaped loop of flexible stranded cable, threaded studs permanently secured onto the ends of the cable, a cross bar having a central arched portion and laterally extending flat end portions and spaced parallel disposed flanges extending longitudinally of thefcross bar, said flat end portions having openings receiving said studs, nuts threaded on said studs and arranged to engage the fiat end portions and be confined between the Aspaced flanges to prevent rotation of the nuts when the latter are vin engagement with the y 50 Hat end portions, and a supporting meansv engaging said central arched portion whereby the strain-insulator is supported in proper alignment with the direction of the load. K, In Witness whereof, I hereunto subscribe 5 my name this 5th day of March, 1928. BURTON M. SMALLEY. 

